Jeremy Grantham, a market investor who is credited with predicting the 2000 and 2008 downturns, said that other investors should get used to more lackluster returns in the stock market in the next 20 years. Grantham says that the poor returns will “break a lot of hearts.”

Grantham told CNBC on Thursday that after a century of handsome gains investors should get inured to lackluster returns in the stock market for the next two decades, according to Market Watch. “In the last 100 years, we’re used to delivering perhaps 6%,” but the United States’ market will be delivering real returns of about 2% or 3% on average over next 20 years,” the value investor and co-founder of Boston-based asset manager GMO told CNBC in a rare interview. This is not great news for those who have a lot of faith in the current economy.

Over the past five years, the S&P 500 index has produced a compound annual growth rate of 8.1%, the Dow Jones Industrial Average has boasted a CAGR of 9.1%, while the Nasdaq Composite Index has registered a compound return of 11.4% over the same period, according to FactSet data. –Market Watch

In spite of the stock market’s plunge in the latter portion of 2018, Grantham believes his prediction is correct because he views the market as still pricey. “This is not incredibly painful, but it’s going to break a lot of hearts when we’re right,” Grantham was quoted as saying.

Grantham has been predicting a meltdown in stocks since last year. He has even said that not even the recent go-slow reversal by the Federal Reserve on rate increases and the European Central Bank’s decision to roll out a fresh batch of bank stimulus will push stocks significantly higher. “You can’t get blood out of a stone,” he told the network. Other economists have warned that when the economy finally collapses this next time, the central bankers and the government will be unable to save anyone.

“This will be limping along; three steps down, two steps back. It’s not a typical experience,” Grantham, who is famous for calling the last two major bubbles in the market, told CNBC’s Wilfred Frost on Thursday. “I was really hoping there would be a magnificent bubble ending to this, as there had been to the three great recent experiences,” he said. “It doesn’t look like it will and, therefore, you’re going to have a decline of a different nature.”